Plug-in part for a plug connector arrangement

ABSTRACT

A plug-in part in the form of a piece of tubing and having a sealing portion, the sealing portion comprising a sealing element enclosing the piece of tubing in a circumferential direction, and a locking portion with at least one undercut. The plug-in part is adapted to be plugged into the receptacle of a coupling part of the plug connector arrangement in order to produce a fluid-tight connection. At least one locking element of the coupling part engages behind the plug-in part in the region of the undercut. In order to develop the plug-in part so as to reduce the risk of the sealing element being adversely affected, the undercut is formed by a protrusion which projects from the outside of the piece of tubing and extends circumferentially merely over a sub-region of the piece of tubing.

This application is divisional of commonly-owned co-pending U.S.application Ser. No. 12/217,499 filed on Jul. 2, 2008, which is acontinuation of international application number PCT/EP2006/011083 filedon Nov. 18, 2006 and which claims the benefit of German applicationnumber 10 2006 002 564.4 filed on Jan. 5, 2006, each of which isincorporated herein by reference in their entirety and for all purposes.

BACKGROUND OF THE INVENTION

The invention relates to a plug-in part for a plug connectorarrangement, the plug-in part being in the form of a piece of tubing andhaving a sealing portion, comprising a sealing element enclosing thepiece of tubing in a circumferential direction, and a locking portionwith at least one undercut, and it being possible for the plug-in partto be plugged into the receptacle of a coupling part of the plugconnector arrangement in order to produce a fluid-tight connection, andfor at least one locking element of the coupling part to engage behindthe plug-in part in the region of the undercut.

Such plug-in parts are used in plug connector arrangements by means ofwhich pipes or hoses can be connected to one another in a releasablemanner. For this purpose, the plug connector arrangement has a couplingpart with a receptacle into which the plug-in part can be plugged. Bymeans of locking elements, the plug-in part can be locked in thecoupling part. The plug-in part is in the form of a piece of tubing and,adjacent to its free end, has a sealing portion with a sealing elementwhich fully encloses the piece of tubing in the circumferentialdirection. If the plug-in part is plugged into the receptacle of thecoupling part, then the sealing element engages in a fluid-tight manneragainst the wall of the receptacle, and a locking element of thecoupling part engages behind at least one undercut, which is positionedin the region of a locking portion of the plug-in part. The plug-in partis thus secured in the direction of its longitudinal axis in thereceptacle of the coupling part, with a fluid-tight connection beingmaintained in the process.

Such plug-in parts are known, for example, from German Utility Model DE86 24 767 U1. In order to lock the plug-in part in the receptacle of thecoupling part, this utility model proposes the use of a locking plughaving two legs and a cross-piece connecting the two legs to oneanother, the legs each forming a locking element. The plug-in part is inthe form of a piece of tubing and has a conical portion which isadjoined by an annular groove which, on its side which is directed awayfrom the conical portion, is bounded by a cylindrical portion. Both thecylindrical portion and the conical portion fully enclose the knownpiece of tubing in the circumferential direction. The rear side of theconical portion, this rear side being directed away from the front sideof the known plug-in part, forms an undercut, and this has two lockingelements engaging behind it when the plug-in part is inserted into thereceptacle of the coupling part.

The fluid-tight connection between the plug-in part and the couplingpart is ensured by a sealing element. If the sealing element isadversely affected, this results in it being possible for a fluid whichis routed through the plug-in part and the coupling part to escape outof the receptacle of the coupling part via the locking portion.

It is an object of the present invention to develop a plug-in part ofthe type mentioned in the introduction so as to reduce the risk of thesealing element being adversely affected.

SUMMARY OF THE INVENTION

This object is achieved according to the invention, in the case of aplug-in part of generic type, by the undercut being formed by aprotrusion which projects from the outside of the piece of tubing andextends circumferentially merely over a sub-region of the piece oftubing.

On account of the undercut extending circumferentially only over asub-region, the plug-in part, in the region of the locking portion, hasan asymmetrical cross-section, as seen with respect to the longitudinalaxis of the plug-in part. It is thus possible, in constructionallystraightforward manner, for the plug-in part to be secured againstrotation in the receptacle of the coupling part. As a result of it thusbeing possible for the plug-in part to be secured in a non-rotatablemanner in the receptacle of the coupling portion, the situation wherethe sealing element is subjected to mechanical loading as a result ofthe plug-in part rotating can be avoided. The plug-in part, which in theregion of the locking portion is formed asymmetrically in respect ofrotation about its longitudinal axis, is thus distinguished by a longservice life.

The plug-in part according to the invention, moreover, has the advantagethat less material is required to produce it than is the case forconventional plug-in parts, because the protrusion which is necessaryfor forming the undercut extends circumferentially merely over asub-region of the piece of tubing. In order to produce the plug-in part,it is thus possible to reduce the amount of material used, so that theplug-in part can be produced particularly cost-effectively.

It is particularly advantageous if the at least one protrusion isadjoined in the circumferential direction by a flattened circumferentialportion of the piece of tubing. The flattened circumferential portionallows surface engagement of the plug-in part, in the region of thelocking portion, against a wall of the receptacle of the coupling part.This can increase the level of mechanical loading to which the plug-inpart can be subjected, when plugged into the receptacle of the couplingpart. Furthermore, providing at least one flattened circumferentialportion makes it possible to produce the plug-in part in a manner whichis particularly optimized in terms of material. Added to this is thefact that providing at least one flattened circumferential portion makesit easier for a user to handle the plug-in part in order to produce afluid-tight connection to a corresponding coupling part since, by way ofthe flattened circumferential portion, the user can intuitively detectthe orientation of the plug-in part which is necessary in order tointroduce the plug-in part into the receptacle.

In the case of a preferred embodiment, the locking portion has twoprotrusions which are located diametrically opposite one another and areconnected to one another via flattened circumferential portions. Theprotrusions each form an undercut, so that the locking elements canengage behind the plug-in part, on diametrically opposite sides, whenthe plug-in part is plugged into the receptacle of the coupling part. Arespective flattened circumferential portion runs between theprotrusions, and allows surface engagement of the plug-in part in thereceptacle of the coupling part. The flattened circumferential portionsare preferably oriented parallel to one another.

It is advantageous if the at least one protrusion is configured in themanner of a bead. As an alternative, it may be provided that theprotrusion is configured in the manner of a pin or wing and projectspreferably radially outwardly from the piece of tubing.

The plug-in part according to the invention is preferably used in a plugconnector arrangement which has a coupling part with locking elementswhich are biased resiliently into a locking position. It is advantageoushere if, in the direction of the front side of the piece of tubing, theat least one protrusion of the plug-in part has a conical end face. Sucha configuration has the advantage that, when the plug-in part isinserted into the corresponding receptacle of the coupling part, alocking element which is biased into the locking position can be pushedto the side by means of the protrusions without an additional actuatingelement having to be actuated by the user for this purpose.

In order to enlarge the region of surface engagement of the plug-in partin the receptacle of the corresponding coupling part, it is advantageousif the protrusion has an outer periphery in the form of a circular arcwhich is formed by a lateral cylindrical surface. This ensures that theprotrusion can also have its outside positioned in surface contactagainst a wall of the receptacle. Merely linear engagement of theprotrusion against the wall of the receptacle is thus avoided.

The undercut, which extends circumferentially merely over a sub-regionof the piece of tubing, is preferably formed by a radially oriented rearside of the protrusion. This makes it possible for the plug-in part tobe secured axially in a particularly reliable manner in the receptacleof the coupling part.

The spacing between the undercut and the front side of the plug-in partis preferably less than 2 times, in particular less than 1.5 times, theexternal diameter of the sealing portion. This makes it possible toensure, on the one hand, a compact construction of the plug-in part andof the corresponding coupling part and, on the other hand, sealedengagement of the sealing element against the wall of the receptacleand, at the same time, reliable locking of the plug-in part in thereceptacle.

The invention relates not just to a plug-in part of the type explainedabove, but also to a plug connector arrangement comprising such aplug-in part and comprising a coupling part which has a receptacle, intowhich the plug-in part can be plugged, and a locking device with atleast one locking element which, in a locking position, penetrateslaterally into a locking region of the receptacle and can be moved intoa release position by means of an actuating element of the couplingpart, the locking region having a cross-section which corresponds to thecross-section of the locking portion of the plug-in part in the regionof the at least one protrusion.

In the case of such a configuration, the locking region of thereceptacle, like the locking portion of the plug-in part, is configuredasymmetrically in respect of rotation about the longitudinal axis of theplug-in part, so that the plug-in part, which engages with surfacecontact against the wall of the locking region, is retained,non-rotationally, in the receptacle.

The receptacle may comprise, for example, two flat wall portions whichare located opposite one another and are connected to one another viatwo wall portions in the form of circular arcs. The arcuate wallportions may have a through-passage via which a respective lockingelement can penetrate laterally into the receptacle, and the flat wallportions serve for the surface engagement of the corresponding flattenedcircumferential portions of the plug-in part.

A more specific explanation will be given by the following descriptionof a preferred embodiment of the invention in conjunction with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective illustration, in exploded form, of a couplingpart of a plug connector arrangement;

FIG. 2 shows a perspective illustration, in exploded form, of a couplingbody and of a locking device of the coupling part from FIG. 1;

FIG. 3 shows a plug connector arrangement having a coupling partaccording to FIG. 1 and a plug-in part according to the invention;

FIG. 4 shows a perspective illustration of the plug-in part from FIG. 3,as seen obliquely from the rear;

FIG. 5 shows a perspective illustration of the plug-in part from FIG. 3,as seen obliquely from the front;

FIG. 6 shows a sectional view along line 6-6 in FIG. 3 prior to theinsertion of the plug-in part into the coupling part;

FIG. 7 shows a sectional view along line 7-7 in FIG. 3 prior to theinsertion of the plug-in part into the coupling part;

FIG. 8 shows a sectional view corresponding to FIG. 6 following theinsertion of the plug-in part into the coupling part;

FIG. 9 shows a sectional view corresponding to FIG. 7 following theinsertion of the plug-in part into the coupling part;

FIG. 10 shows a sectional view corresponding to FIG. 7 as the plug-inpart is being released from the coupling part; and

FIG. 11 shows a partially cut-away plan view of the coupling part as theplug-in part is being released.

DETAILED DESCRIPTION OF THE INVENTION

The drawing illustrates, schematically, a plug connector arrangementthat is designated overall by the reference numeral 10 and has acoupling part 11 and a plug-in part 12 which, in order to produce afluid-tight connection, can be inserted into a receptacle 14 of thecoupling part.

The coupling part 11 is formed in three parts and comprises a couplingbody 16, which is substantially cylindrical and includes the receptacle14, as well as a locking device 18 and an actuating sleeve 20.

As is clear, in particular, from FIGS. 6 to 9, the receptacle 14 isconfigured as a through-bore which passes through the coupling body 16and forms a locking region 24, which opens out in the front side 23 ofthe coupling body 16, and an adjoining sealing region 25. The sealingregion 25 is cylindrically symmetrical, whereas the locking region 24has two flat wall portions 28, 29 which are located diametricallyopposite one another and are connected to one another via wall portions,30, 31 in the form of circular arcs. The flat wall portions 28, 29 areoriented parallel to one another.

On a level with the locking region 24, the coupling body 16 has twooblong holes 33, 34 which open out laterally into the locking region 24,pass through the coupling body 16 and have sliding surfaces 35, 36oriented obliquely in relation to the longitudinal axis of the couplingbody.

A plurality of guide ribs 39 project radially outwardly, at a uniformspacing from one another in the circumferential direction, from theoutside 38 of the coupling body 16.

The locking device 18 comprises a U-shaped spring element 41 with twolegs 42, 43 which are oriented parallel to the longitudinal axis of thecoupling body 16 and are connected to one another via an arcuatecross-piece 44. The free ends of the legs 42 and 43 are adjoined in eachcase by a respective locking pin 45, 46 which is oriented at rightangles to the respective leg 42, 43 and penetrates into a respectiveoblong hole 33, 34 and passes through the same. This is clear fromFIG. 1. In the region of their free ends, the locking pins 45, 46project in each case, by way of a first end region 48, beyond theoutside 38 of the coupling body 16, and the locking pins 45 and 46 alsoproject beyond the outside 38 by way of a second end region 49, whichadjoins the respective leg 42, 43. The locking pins 45, 46 can begripped in each case at their two end regions 48, 49 on the outside 38of the coupling body 16, so that starting from their locking position,which is illustrated in FIG. 1, the locking pins 45, 46 can betransferred, counter to an elastic restoring force exerted by the springelement 41, into a release position, which is illustrated in FIGS. 10and 11, the locking pins sliding along the sliding surfaces 35 and 36 ofthe oblong holes 33, 34, respectively. In their release position, thelocking pins 45, 46 are spaced apart from one another to a greaterextent than in their locking position.

In order to displace the locking pins 45, 46 along the sliding surfaces35, 36, use is made of the actuating sleeve 20 which, on the end side,has an annular shoulder 51 which juts back in the inward direction andhas two shoulder portions 52, 53 which are located diametricallyopposite one another and, between them accommodate a respective inwardlyprojecting latching protrusion 55, 56. Directly adjacent to the latchingprotrusions 55 and 56, a respective stop element 58 is integrally formedon the shoulder portions 52 and 53, and this stop element, in thedirection away from the front side 23, has a stop surface 59 orientedobliquely in relation to the longitudinal axis of the coupling body 16.

The actuating sleeve 20 can be placed onto the coupling body 16 at thefront, in which case it latches to the coupling body 16, which, in linewith the front side 23, has two outer protrusions 61, behind which thelatching protrusions 55 and 56 of the actuating sleeve 20 engage.

If the actuating sleeve 20 is displaced along the coupling body 16 inthe direction away from the front side 23, then the stop surfaces 59engage in each case against a respective end region 48, 49 of thelocking pins 45 and 46 and, as the actuating sleeve 20 is displacedfurther, the locking pins 45, 46 are displaced along the associatedsliding surfaces 35, 36 in the direction of their release position.

The configuration of the plug-in part 12 according to the invention isparticularly clear from FIGS. 3, 4 and 5. The plug-in part 12 is in theform of a piece of tubing and has a sealing portion 65 with an annulargroove 66 which runs all the way round in the circumferential directionand in which a sealing ring 67 is disposed. The sealing portion 65 isadjoined by a locking portion 69 having two protrusions in the form ofouter beads 70, 71 which are located diametrically opposite one another,extend circumferentially merely over a sub-region of the plug-in partand are connected to one another via flattened circumferential portions73, 74. The spacing between the flattened circumferential portions 73,74 is identical to the external diameter of the sealing portion 65. Theflattened circumferential portions 73, 74 are oriented parallel to oneanother.

The outer beads 70, 71 have a respective conical end face 76, 77, whichwidens in the direction away from the free end of the plug-in part. Theconical end faces 76, 77 are adjoined by a respective lateralcylindrical surface 79, 80, which is arcuate in cross-section and isadjoined in the axial direction by a respective radially orientedterminating surface 82, 83. The terminating surfaces 82, 83 each form anundercut of the plug-in part 12.

At the outer beads 70, 71, the cross-section of the plug-in part 12corresponds to the cross-section of the locking region 24 of thecoupling body 16. In order to produce a fluid-tight connection, theplug-in part 12 can thus be inserted into the receptacle 14 of thecoupling body 16, the plug-in part 12 engaging with surface contactagainst the wall of the receptacle 14 both in the region of the sealingportion 65 and in the region of the locking portion 69. If the plug-inpart 12 is inserted into the receptacle 14, then the conical end faces76, 77 engage against the locking pins 45, 46, so that, as the plug-inpart 12 is inserted further into the receptacle 14, these locking pinsare pushed laterally outwards and the plug-in part 12 can thus be guidedthrough between the locking pins 45, 46. The sealing portion 65 of theplug-in part 12 can thus be positioned on a level with the sealingregion 25 of the coupling body 16, the sealing ring 67 engaging in afluid-tight manner against the wall of the sealing region 25. This isparticularly clear from FIGS. 8 and 9.

The plug-in part 12 can be inserted into the receptacle 14 until thelocking pins 45, 46, which are biased resiliently into their lockingposition, engage behind the undercuts, which are formed by the outerbeads 70, 71, and thus secure the plug-in part axially in the receptacle14. The locking pins 45, 46 therefore form locking elements of thecoupling part 11. On account of both the locking portion 69 of theplug-in part 12 and the locking region 24 of the coupling body 16 beingconfigured asymmetrically in respect of rotation about the longitudinalaxis of the plug-in part 12 and of the coupling body 16, the plug-inpart 12 is retained in a rotationally fixed manner in the receptacle 14.The sealing ring 67 is thus relieved of rotary movement, which couldresult in wear to the sealing ring. Mechanical wear to the sealing ring67 is thus kept to a particularly low level. Moreover, the asymmetricalconfiguration, in respect of rotation about the longitudinal axis of theplug-in part 12 and of the coupling body 16, ensures that the plug-inpart 12 can only be inserted into the receptacle 14 with predefinedorientation. Furthermore, providing the flattened circumferentialportions 73, 74 allows the plug-in part 12 to be produced in a mannerwhich is optimized in terms of material. The flattened circumferentialportions 73, 74, moreover, ensure that it is also possible for theplug-in part 12, in the region of the locking portion 69, to bepositioned in surface contact against the wall of the receptacle 14.

What is claimed is:
 1. Plug-in part for a plug connector arrangement,said plug-in part comprising: a piece of tubing, a sealing portion, saidsealing portion comprising a sealing element enclosing the piece oftubing in a circumferential direction, and a locking portion with atleast one undercut, the at least one undercut being formed by twoprotrusions which project from outside of the piece of tubing and extendcircumferentially over a sub-region of the piece of tubing, providingthe piece of tubing with an asymmetrical cross-section in a region ofthe locking portion, wherein: the plug-in part is adapted to be pluggedinto a receptacle of a coupling part of the plug connector arrangementin order to produce a fluid-tight connection, the plug in part isadapted to receive at least one locking element of the coupling part ina region of the at least one undercut, the asymmetrical cross-sectionsecures the plug-in part against rotation when plugged into the couplingpart, the two protrusions are located diametrically opposite one anotherand are connected to one another via flattened circumferential portionsof the locking portion, and the two protrusions extend radially from thepiece of tubing to a greater extent than the flattened circumferentialportions.
 2. Plug-in part according to claim 1, wherein the protrusionscomprise beads.
 3. Plug-in part according to claim 1, wherein in adirection of a free end of the piece of tubing, the protrusions have aconical end face.
 4. Plug-in part according to claim 1, wherein theprotrusions have an outer periphery in a form of a circular arc which isformed by a lateral cylindrical surface.
 5. Plug-in part according toclaim 1, wherein the at least one undercut is formed by a radiallyoriented rear side of the protrusions.
 6. Plug-in part according toclaim 1, wherein a spacing between the at least one undercut and a freeend of the plug-in part is less than 2 times an external diameter of thesealing portion.